When, in pursuing the catechetical exercise, a question is asked from an announcement, there is first a call upon the attention, and an exercise of mind upon the _question_ asked, the words of which must be translated by the pupil into their proper ideas, which accordingly he must both perceive and understand. He has then to revert to the _ideas_ (not the words) contained in the original announcement, the words of which are perhaps still ringing in his ears; and these he must also perceive and reiterate in his mind, before he can either understand them or prepare to give an answer. At this point the child is necessarily in possession of the ideas--the truths--conveyed by the announcement; and therefore at this point one great end of the teacher has in so far been gained. But the full benefit of the exercise, in so far as it is capable of fixing these truths still more permanently on the memory, and of disciplining the mind, has not yet been exhausted. After the pupil has reiterated in his mind the ideas contained in the original sentence, or passage announced, he has again to revert to the question of the teacher, and compare it with the several ideas which the announcement contains. He has then to chuse from among them,--all of them being still held in review by the mind,--the particular idea to which his attention has been called by the question;--and last of all, and which is by no means the least as a mental exercise, he has to clothe this particular idea in words, and construct his sentence in such a way as to make it both sense and grammar. In this last effort, it is worthy of remark, children, after having been but a short while subjected to this exercise, almost invariably succeed, although they know nothing about grammar, and may perhaps never have heard of the name. But even this is not all. There has as yet been only one question asked, and the answer to this question refers to only one idea contained in the announcement. But it embraces at least three several ideas; and each of these ideas, by the catechetical exercise, is capable of originating other questions, perfectly distinct from each other, and each of which gives rise to a similar mental process, and with equally beneficial results, in exercising and strengthening the powers of the mind.